Single layer multi mode antenna for wireless power transmission using magnetic field coupling

ABSTRACT

Various embodiments of a single structure multiple mode antenna are described. The antenna is preferably constructed of a single layer having a first inductor coil that is electrically connected in series with a second inductor coil. The antenna is constructed having a plurality of electrical connections positioned along the first and second inductor coils. A plurality of terminals facilitates connection of the electrical connections thereby providing numerous electrical connection configurations and enables the antenna to be selectively tuned to various frequencies and frequency bands.

TECHNICAL FIELD

The present disclosure relates generally to the wireless transmission ofelectrical energy and data. More specifically, this application relatesto an antenna that facilitates the wireless transmission of data andelectrical energy at multiple operating frequency bands.

BACKGROUND

Wireless energy transfer is useful in cases where the interconnection ofwires may be inconvenient, hazardous or impossible. In recent years,applications employing near-field wireless power and/or datatransmission have gained prominence in areas such as consumerelectronics, medical systems, military systems and industrialapplications. Near-field communication enables the transfer ofelectrical energy and/or data wirelessly through magnetic fieldinduction between a transmitting antenna and a corresponding receivingantenna. Near-field communication interface and protocol modes aredefined by ISO/IEC standard 18092.

However, near-field communication is often not optimal because prior artantennas that facilitate the wireless transfer of electrical powerand/or data operate inefficiently. In such cases, the amount ofelectrical energy received by the corresponding antenna is generallysignificantly less than the amount of electrical energy initiallytransmitted. In addition, data that is received may be incomplete or maybecome corrupted. In addition, near-field communication generallysuffers from reduced wireless transfer distances, i.e., the transmissionrange, and physical antenna orientation issues. These inefficiencies ofnear field communication are largely due to the low quality factor ofthe prior art antennas in addition to the inefficient large size ofprior art antennas. In general, prior art near field communicationantennas have a relatively large size that hinders efficient operationand wireless transmission. Size and efficiency are often a tradeoff, aproblem which becomes more acute when multiple wireless operations aredesired, i.e., multiple modes of operation. A solution to inefficientnear-field communication is antenna integration.

Inductive solutions transfer power and/or data between two inductorcoils that are placed in close proximity to each other. This technology,for example, facilitates the deployment of inductive charging “hotspots” that enables wireless electrical charging of electronic devicesby simply placing them near a charging “hot spot”, such as on a surfaceof a table. However, for these systems to operate efficaciously, therespective transmitter and receiver antennas are required to not only belocated in close proximity to each other but, in addition, must also bephysically positioned in a specific orientation with respect to oneanother. Typically, these prior art antennas require that they arephysically positioned in near perfect alignment such that the centers ofthe respective transmitting and receiving antennas are oriented inperfect opposition to each other in order to operate efficaciously. Thisgeneral requirement for near perfect physical alignment of thetransmitting and receiving antennas typically leads to poor near fieldcommunication performance as it is challenging to achieve perfectalignment of the opposing transmitting and receiving antennas to ensureproper wireless power and/or data transfer.

As a result, use of these prior art antennas leads to near fieldcommunication that is generally not reliable and significantly reducedoperating efficiency. As defined herein “inductive charging” is awireless charging technique that utilizes an alternating electromagneticfield to transfer electrical power between two antennas. “Resonantinductive coupling” is defined herein as the near field wirelesstransmission of electrical energy between two magnetically coupled coilsthat are part of two spaced apart resonant circuits that are tuned toresonate at the same frequency. “Magnetic resonance” is defined hereinas the excitation of particles (as atomic nuclei or electrons) in amagnetic field by exposure to electromagnetic radiation of a specificfrequency.

Various multimode wireless power solutions have been developed toaddress these antenna positioning and proximity limitations andconcomitant of reliability & efficiency issues. In some cases, operatingfrequency bands have been reduced, for example, a frequency band thatranges from about 150 kHz to about 250 kHz to increase range from about15 mm to about 20 mm has been achieved by resonating the receivingantenna at a frequency that is about the same as the frequency of thetransmitting antenna, both of which are similar to the frequency atwhich power transfer is taking place. However, such solutions have notsufficiently addressed the need to provide increased efficient wirelesstransfer with multiple mode operation capability through modification ofthe antenna structure.

Inductive and resonance interface standards have been developed tocreate global standards for wireless charging technologies. “Qi” is awireless inductive power transfer standard/specification. Specifically,the Qi wireless inductive power transfer standard is an interfacestandard that was developed by the Wireless Power Consortium. The Qiinterface standard is a protocol generally intended to facilitatetransfer of low electrical power up to about 15 W at frequencies rangingfrom 100 kHz to about 200 kHz over distances ranging from about 2 mm toabout 5 mm.

“Rezence” is a competing interface standard developed by the Alliancefor Wireless Power (A4WP) for wireless electrical power transfer basedon the principles of magnetic resonance. Specifically, the Rezenceinterface standard currently supports electrical power transfer up toabout 50 W, at distances up to about 5 cm. Unlike the Qi interfacestandard, the Rezence interface standard utilizes an increased frequencyof about 6.78 MHz+/−15 kHz.

In addition, there exists a third standard developed by the PowerMatters Alliance (PMA) that operates in the frequency range of about 100kHz to about 350 kHz. Unlike prior art multi-band antennas, themulti-band single structure antenna of the present disclosure is capableof receiving and/or transmitting signals and/or electrical energy acrossall of these standards with one antenna.

Currently these standards are the preeminent standards for wirelesspower technology in consumer electronics. Although these standards arerelatively new to the market, the surge in development of small portablewireless devices and the proliferation of wireless transmissionsolutions into other wireless applications increases the need for, andadoption of, these standards. The Qi interface standard, released in2010, has already been widely adopted. The Qi interface standard iscurrently incorporated into more than 20 million products world-wide.

Antennas are a key building block in the construction of wireless powerand/or data transmission systems. As wireless technologies havedeveloped, antennas have advanced from a simple wire dipole to morecomplex structures. Multi-mode antennas have been designed to takeadvantage of different wireless interface standards. For example, Qiinductive wireless charging was first demonstrated in an Androidsmartphone more than four years ago. In 2015, the Samsung® Galaxy 56®supports two wireless charging standards, namely PMA and WPC's Qi. Thissolution, however, addresses inductive interface standards only. Giventhe differences in, for example, performance efficiencies, size,transfer range, and positioning freedom between inductive transmissionversus resonance-based transmission, what is needed is a single antennaboard that works with all types of wireless charging standards, forexample, the PMA standard, WPC's Qi standard and A4WP's Rezencestandard.

Furthermore, some wireless transmission applications will utilize acombination of standards-based and/or non-standards-based transferprotocols. The multi-band single structure antenna of the presentdisclosure is capable of receiving and/or transmitting signals and/orelectrical energy across any combination of standards-based and/ornon-standards-based transfer protocols with one antenna.

Prior art “multi mode” antennas, referred to as “Two-Structure DualMode” (TSDM) antennas, are typically constructed having two discreteantenna structures that are positioned on a substrate. The two discreteantenna structures that comprise a TSDM antenna operate independent ofeach other and require separate terminal connections to each of therespective independent antenna. FIG. 1 illustrates an example of such aprior art two-structure dual mode antenna 10 which comprises a firstexterior inductor 12 and a second, separate interior inductor 14, eachantenna having a positive and negative terminal connection respectivelythat are not electrically connected. However, such TSDM antennas have arelatively large footprint which comprises a significant amount of spaceand surface area. Such TSDM antennas are therefore, not ideally suitedfor incorporation with small electronic devices or positioned withinsmall confined spaces.

Two-structure multi-mode (TSMM) antennas 10 are generally constructedsuch that both the separate exterior and interior inductors 12, 14 eachhave a specific inductance. Thus, the exterior inductor 12 isconstructed having a specific number of exterior inductor turns and theinterior inductor 14 is constructed having a specific number of interiorinductor turns. In this structure, the two respective coils operate asindependent antennas. Coil-based TSMM antennas fundamentally require alarge amount of area to enable better performance. Specifically, antennacoupling between the exterior and interior antennas require that they bepositioned a distance away from each other such that energy generatedfrom one antenna is not absorbed by the other. Furthermore, in atraditional TSMM configuration, when the “interior” antenna isoperating, the area extending from the outermost trace of the internalantenna to the outermost trace of the exterior antenna is not beingutilized and, thus, is “wasted” space.

SUMMARY

The present disclosure provides various embodiments of an antenna thatis capable of wirelessly receiving and/or transmitting electrical powerand/or data between different locations. Specifically, the antenna ofthe present disclosure is designed to enable wireless reception ortransmission of electrical power and/or data over multiple frequenciessuch as the specifications established by the Qi and Rezence interfacestandards, as previously mentioned. The multi-mode antenna of thepresent disclosure is of a single structure comprising at least twoinductor coils that are electrically connected in series. In anembodiment, the single structure multi-mode antenna of the presentdisclosure may comprise a composite of at least one substrate on whichat least one electrically conductive filar is disposed. Furthermore, atleast one of the substrate layers that comprise the single structureantenna may be composed of a different material. Alternatively, thesingle structure antenna of the present disclosure may be constructedwithout a substrate.

The single structure antenna of the present disclosure preferablycomprises at least two inductor coils that are electrically connected inseries. Each of the inductors is preferably composed of an electricallyconductive material such as a wire, which may include, but is notlimited to, a conductive trace, a filar, a filament, a wire, orcombinations thereof. It is noted that throughout this specification theterms, “wire”, “trace”, “filament” and “filar” may be usedinterchangeably. As defined herein, the word “wire” is a length ofelectrically conductive material that may either be of a two dimensionalconductive line or track that may extend along a surface oralternatively, a wire may be of a three dimensional conductive line ortrack that is contactable to a surface. A wire may comprise a trace, afilar, a filament or combinations thereof. These elements may be asingle element or a multitude of elements such as a multifilar elementor a multifilament element. Further, the multitude of wires, traces,filars, and filaments may be woven, twisted or coiled together such asin a cable form. The wire as defined herein may comprise a bare metallicsurface or alternatively, may comprise a layer of electricallyinsulating material, such as a dielectric material that contacts andsurrounds the metallic surface of the wire. A “trace” is an electricallyconductive line or track that may extend along a surface of a substrate.The trace may be of a two dimensional line that may extend along asurface or alternatively, the trace may be of a three dimensionalconductive line that is contactable to a surface. A “filar” is anelectrically conductive line or track that extends along a surface of asubstrate. A filar may be of a two dimensional line that may extendalong a surface or alternatively, the filar may be a three dimensionalconductive line that is contactable to a surface. A “filament” is anelectrically conductive thread or threadlike structure that iscontactable to a surface.

In a preferred embodiment, the at least two inductor coils are disposedon an external surface of one of the plurality of substrates.Alternatively, at least one of the plurality of inductor coils may bedisposed on each of the substrates that comprise the antenna structure.At least one via may be provided that connects at least two of theconductive materials that comprise the inductors of the antenna. In apreferred embodiment, the at least one via may be provided to create anelectrical shunt connection between the coils, or portions thereof. Asdefined herein the term “shunt” means an electrically conductive pathwaythat is created by electrically joining two points of a circuit suchthat an electrical current or an electrical voltage may passtherethrough.

The inductor coils are strategically positioned and electricallyconnected in series to facilitate the reception and/or transmission ofwirelessly transferred electrical power or data through near fieldmagnetic induction at either, both or all frequency ranges of about 100kHz to about 200 kHz (Qi interface standard), 100 kHz to about 350 kHz(PMA interface standard), 6.78 MHz (Rezence interface standard), oralternatively at a frequency being employed by the device in aproprietary recharging mode. In addition, the antenna of the presentdisclosure may be designed to receive or transmit over a wide range offrequencies on the order of about 1 kHz to about 1 GHz or greater inaddition to the Qi and Rezence interfaces standards.

In addition to enabling dynamic adjustment of the antenna's operatingfrequency, the single structure of the present disclosure also enablesdynamic adjustment of its self-resonance frequency. Such self resonantfrequencies are typically utilized for radio frequency (RF)communication such as a cellular phone or radio. The single structureantenna of the present application is capable of self resonantfrequencies that range from about 1 kHz to about 500 GHz. Furthermore,the single structure antenna of the present application is capable ofdynamically adjusting the inductance exhibited by the antenna.

Such a dynamic adjustment of at least one of the operating frequency,resonance frequency and inductance of the antenna is preferablyaccomplished through modifying the various connections within theantenna. More specifically, the operating frequency, the self-resonancefrequency and/or the inductance of the antenna can be changed bymodifying the various “tapped” inductance coil electrical connectionsthat are strategically positioned therewithin. Thus, by modifying thesequence of the electrical connections between the at least variousportions of the electrically connected inductor coils that comprise theantenna, the operating frequency, resonance frequency and/or inductancecan be dynamically adjusted to meet various application requirements.Moreover, by dynamically adjusting the electrical connections within theantenna of the present disclosure, the separation distance betweenadjacent antennas that facilitates data or electrical power transfer canalso be adjusted to meet specific application requirements. As definedherein, the term “tapped” means an electrical connection between atleast two points.

In one or more embodiments of the present disclosure, a multi-modesingle structure antenna includes a first conductive wire forming afirst coil having N₁ number of turns with spaced apart first and secondfirst coil ends, the first coil contactable to a substrate surface,wherein the first coil is capable of generating a first inductance. Theantenna also includes a second conductive wire forming a second coilhaving N₂ number of turns with spaced apart first and second coil ends,the second coil capable of generating a second inductance positionedwithin an inner perimeter formed by the first coil. The antenna furtherincludes a first terminal electrically connected to the first end of thefirst coil, a second terminal electrically connected to the second endof the second coil and a third terminal electrically connected alongeither of the first or second coils. The antenna also includes wherein atunable inductance is generatable by selecting a connection between twoof the first, second and third terminals.

One or more embodiments include a gap disposed between the innerperimeter of the first coil and an outer perimeter of the second coil.One or more embodiments include wherein the gap is at least about 0.1mm. One or more embodiments include wherein the first conductive wirecomprises two or more filars electrically connected in parallel. One ormore embodiments include wherein the second conductive wire comprisestwo or more filars electrically connected in parallel. One or moreembodiments include wherein the first terminal is electrically connectedto the first end of the first coil, the first end of the first coildisposed at an end of the first wire of the first coil located at anoutermost first coil perimeter, the third terminal is electricallyconnected to the first end of the second coil positioned at a secondcoil outer perimeter, and the second terminal is electrically connectedto the second end of the second coil located along an interior perimeterof the second coil pattern.

One or more embodiments include wherein a selection circuit iselectrically connected to at least one of the first, second, and thirdterminals. One or more embodiments include wherein the selection circuitcomprises at least one component selected from the group consisting of acapacitor, a resistor, and an inductor. One or more embodiments includewherein N₁ is at least one and N₂ is at least two. One or moreembodiments include wherein N₂ is greater than N. One or moreembodiments include wherein each terminal has a terminal lead portionthat extends between a coil connection point and a terminal end, thecoil connection point electrically connected to either of the first andsecond conductive wires of the first and second coils respectively, andwherein the terminal lead portion extends over at least a portion ofeither of the first and second conductive wires of the first and secondcoils respectively.

One or more embodiments include wherein a plurality of first vias arepositioned adjacently along a right side of a length of the terminallead portion and a plurality of second vias are positioned along a leftside of the length of the terminal lead portion and opposed from theplurality of first vias so that each of the plurality of first viasopposes one of the plurality of second vias, wherein the respectiveopposing vias of the plurality of first and second vias are electricallyconnected to the same conductive wire of either of the first or secondcoils, thereby establishing a conductive electrical path therebetweenthat bypasses the terminal lead portion. One or more embodiments includewherein at least the first conductive wire or the second conductive wirehas a variable wire width. One or more embodiments include the antennahaving a quality factor greater than 10.

One or more embodiments include wherein an electrical signal selectedfrom the group consisting of a data signal, an electrical voltage, anelectrical current, and combinations thereof is receivable by at leastthe first and second coils. One or more embodiments include wherein anelectrical signal selected from the group consisting of a data signal,an electrical voltage, an electrical current, and combinations thereofis transmittable by at least the first and second coils. One or moreembodiments include wherein the substrate comprises material composed ofan electrically insulative material selected from the group consistingof a polyimide, an acrylic, fiberglass, polyester, polyether imide,polytetrafluoroethylene, polyethylene, polyetheretherketone (PEEK),polyethylene napthalate, fluropolymers, copolymers, a ceramic material,a ferrite material, and combinations thereof.

One or more embodiments include wherein the antenna is capable ofreceiving or transmitting within a frequency band selected from thegroup consisting of about 100 kHz to about 250 kHz, about 250 kHz toabout 500 kHz, 6.78 MHz, 13.56 MHz, and combinations thereof. One ormore embodiments include wherein the antenna is capable of receiving ortransmitting at frequencies of at least 100 kHz. One or more embodimentsinclude wherein a tunable operating frequency is generatable byselecting a connection between two of the first, second, and thirdterminals.

In a preferred embodiment, various materials may be incorporated withinthe structure of the antenna to shield the coils from magnetic fieldand/or electromagnetic interference and, thus, further enhance theantenna's electrical performance. Specifically, magnetic field shieldingmaterials, such as a ferrite material, may be positioned about theantenna structure to either block or absorb magnetic fields that createundesirable proximity effects that increase electrical impedance withinthe antenna. As will be discussed in more detail, these proximityeffects generally increase electrical impedance within the antenna whichresults in a degradation of the quality factor. In addition, themagnetic field shielding materials may be positioned about the antennastructure to increase inductance and/or act as a heat sink within theantenna structure to minimize over heating of the antenna. Furthermore,such materials may be utilized to modify the magnetic field profile ofthe antenna. Modification of the magnetic field(s) exhibited by thesingle structure antenna of the present disclosure may be desirable inapplications such as wireless charging. For example, the profile andstrength of the magnetic field exhibited by the antenna may be modifiedto facilitate and/or improve the efficiency of wireless power transferbetween the antenna and an electric device such as a cellular phone.Thus, by modifying the profile and/or strength of the magnetic fieldabout an electronic device being charged, minimizes undesirableinterferences which may hinder or prevent transfer of data or anelectrical charge therebetween.

Thus, the single structure antenna of the present disclosure is of anefficient design that is capable of operating over multiple frequencieshaving an optimized inductance and quality factor that comprises atleast two inductor coils that are electrically connected in series. Thesingle structure antenna of the present disclosure enables the antennato be tuned to a multitude of customizable frequencies and frequencybands to facilitate optimized wireless transfer of electrical energyand/or data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of a prior art four terminaltwo-structure dual mode antenna.

FIG. 2 shows an embodiment of a three terminal single structure multiplemode antenna of the present disclosure comprising a switch circuit.

FIG. 2A is an electrical schematic diagram of the three terminal singlestructure multiple mode antenna illustrated in FIG. 2.

FIG. 3 illustrates an embodiment of a three terminal single structuremultiple mode antenna of the present disclosure.

FIG. 3A is an electrical schematic diagram of the three terminalembodiment of the antenna shown in FIG. 3.

FIG. 3B is an embodiment of a first layer of a multi-layer singlestructure multiple mode antenna of the present disclosure.

FIG. 3C is an embodiment of a second layer of a multi-layer singlestructure multiple mode antenna of the present disclosure.

FIG. 3D illustrates a magnified view of a portion of an inductor coilhaving a plurality of shunted via connections.

FIG. 3E is an embodiment of a three terminal single structure multiplemode antenna of the present disclosure in which the respective terminalsare connected to a single filar.

FIG. 3F is a magnified view showing an embodiment in which the filars ofan inductor coil are electrically bypassing the terminal lines.

FIG. 4 is an electrical schematic diagram of the four terminal antennaembodiment of the present disclosure shown in FIG. 4.

FIG. 5 shows an embodiment of a single structure multiple mode antennaof the present disclosure comprising a conductive filar with a variablewidth.

FIGS. 6A-6E illustrate cross-sectional views of different embodiments ofthe antenna of the present disclosure with different ferrite materialshielding configurations.

FIG. 7 is a flow diagram that illustrates an embodiment of a fabricationprocess of a single structure antenna of the present disclosure.

FIG. 8A illustrates an embodiment of the magnetic field strengthsgenerated by a single turn coil antenna.

FIG. 8B illustrates an embodiment of the magnetic field strengthsgenerated by a two turn coil antenna.

FIG. 8C illustrates an embodiment of the magnetic field strengthsgenerated by a three turn coil antenna.

FIG. 9 shows an embodiment of a two coil antenna fabricated from a metalstamping process.

FIG. 10 is a flow chart that illustrates an embodiment of a fabricationprocess of a single structure antenna of the present disclosure having aunitary body structure.

FIG. 11 shows a theoretical embodiment of a single structure antenna ofthe present disclosure comprising n+1 number of terminals.

FIGS. 12A-12C illustrate various embodiments of electrical switchconfigurations that provide different electrical connections betweeninductor coils.

FIG. 13 is a flow chart that illustrates an embodiment of operating asingle structure antenna of the present disclosure.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth byway of examples in order to provide a thorough understanding of therelevant teachings. However, it should be apparent to those skilled inthe art that the present teachings may be practiced without suchdetails. In other instances, well known methods, procedures, components,and/or circuitry have been described at a relatively high-level, withoutdetail, in order to avoid unnecessarily obscuring aspects of the presentteachings.

The antenna and communication system thereof of the present disclosureprovides for improved induction communication, such as near fieldcommunication. More specifically, the antenna of the present disclosureis of a single structure design that enables coupled magnetic resonance.Coupled magnetic resonance is an alternative technology that whenappropriately designed, can provide for increased wireless powertransfer and communication efficiencies and is less dependent ofphysical orientation and positioning requirements of prior art antennas.As a result, the antenna of the present disclosure provides for improvedwireless transfer efficiency and a better user experience.

The multi-band single structure antenna of the present disclosure alsoenables increased transmission range. As will be discussed in moredetail, the structure of the antenna of the present disclosure enablestuning of the operating frequency. This enables the operator to quicklymodify the receiving antenna's operating frequency to match thefrequency of the transmitted signal or, alternatively, transmit a signalat an increased frequency using a frequency multiplier to match theincreased operating frequency of a receiving antenna.

Furthermore, the single structure antenna of the present disclosure mayalso comprise a selection circuit which may be capable of conditioningor modifying the received or transmitted signal. An example of whichincludes modifying the operating frequency of the antenna by a frequencymultiplying factor to increase range.

In addition, the antenna of the present disclosure enables increasedoperating frequencies. Operating at a higher frequency range providesfor smaller antenna form factors. For example, consider a generictransmitting and receiving antenna combination both operating at afrequency (ω) that are spaced a distance d apart and have a couplingfactor, k. The transmitting antenna has a transmitting antennainductance (LT_(x)) and the receiving antenna has a receiving antennainductance (LR_(x)). In this scenario, the induced voltage at thereceiving antenna is given by the formula:

V _(induced) ˜ωk√{square root over (L _(TX) L _(Rx))}

Based on the equation above, if the frequency of operation (ω) isincreased, the respective transmitting and receiving antenna inductancesrequired to produce a similar induced voltage is reduced, given asimilar coupling factor, k. Thus, as a result, smaller inductors thatrequire less space can be utilized for the respective antennas. Forexample, if the form factor, i.e., surface area of the coils is keptnearly identical having a similar coupling coefficient, a thinnerreceiver coil or transmitter coil may be possible by designing for areduced receiving or transmitting inductance because of the increasedoperating frequency (ω).

In wearable electronics, where space is at a premium, operating at ahigher frequency and tuning the respective inductors of the receivingantenna closer to the intended frequency of transmission provides thepotential of increased performance, i.e., improved quality factor andincreased induced voltages in a smaller form factor.

In contrast to the prior art TSMM antenna, the single-structuremulti-mode (SSMM) antenna of the present disclosure provides anefficient design that enables the reception and transmission of amultitude of a non-limiting range of frequencies which includes thefrequency specification of the Qi and Rezence interface standards, inaddition to many other wireless electrical power transfer standards. Inaddition, the single structure multi-mode antenna of the presentdisclosure enables multiple communication based standards such as, butnot limited to, near field communication (NFC), radio frequencyidentification (RFID), multi-mode standard transponder (MST), inaddition to a host of frequency standards that operate at frequenciesgreater than about 400 MHz. The physical mechanism of these multiple“power” transfer and/or “communications” modes may be purely magnetic,such as via magnetic fields, electromagnetic, such as viaelectromagnetic waves, electrical, such as via capacitive interactionsor piezoelectric action. Piezoelectric power transfer and/orcommunication modes would generally require a unique piezoelectricmaterial such as barium titanate, lead zirconate titanate, or potassiumniobate that is able to transduce acoustic signals to electrical signalsand vice versa.

Specifically, the single-structure multi-mode (SSMM) antenna of thepresent disclosure facilitates either or both the transmission andreception of wirelessly transmitted electrical power and/or data. Theunique design and construction of the SSMM antenna of the presentdisclosure, provides an antenna having optimized electrical performancein a reduced form factor.

In addition, the single structure antenna of the present disclosure mayalso comprise a plurality of materials such as various ferrite materialsto block magnetic fields from adjacent wire strands of the plurality ofcoils. Thus, these magnetic blocking materials shield adjacent wirestrands from the adverse effects of magnetic fields on the propagationof electrical power and/or electric signals.

Specifically, the present disclosure provides an antenna having a singlecoil structure in which a multitude inductor coils are electricallyconnected in series. Such a construction provides for an antenna havinga compact design that enables adjustment or tuning of the inductancewithin the antenna which results in the ability to tune multiple antennafrequencies.

Turning now to the drawings, FIGS. 2, 2A, 3, 3A, 3B, 3C, 3D, 3E, 4, 4A,9 and 11 illustrate different embodiments and configurations of a singlestructure multi-mode antenna of the present disclosure. FIG. 2illustrates an embodiment of a three-terminal antenna 20 of the presentdisclosure. As illustrated, the antenna 20 comprises a substrate 22 onwhich is positioned a first, outer coil 24 and a second, interior coil26. More specifically, both the first and second coils 24, 26 arepositioned on an external surface 28 of the substrate 22.

As shown, the first outer coil 24 comprises a first electricallyconductive material 30 such as a trace or filar which is positioned in acurved orientation with respect to the surface 28 of the substrate 22.In a preferred embodiment, the trace or filar 30 is positioned in aspiral or serpentine orientation with respect to the surface 28 of thesubstrate 22 having “N₁” number of turns. The second interior coil 26comprises a second electrically conductive material 32 such as a traceor filar positioned in a curved orientation with respect to the surface28 of the substrate 22. In a preferred embodiment, the second trace orfilar 32 is positioned in a spiral or serpentine orientation withrespect to the surface 28 of the substrate 22 having “N₂” number ofturns.

In a preferred embodiment as shown in FIG. 2, the second interior coil26 is positioned within an inner perimeter formed by the first outercoil 24. As defined herein, a “turn” is a single completecircumferential revolution of the electrically conductive filarpositioned on the surface of a substrate. As illustrated in the exampleantenna shown in FIG. 2, the first outer coil 24 comprises 3 turns (N₁)and the second interior coil 26 comprises 14 turns (N₂). In a preferredembodiment, the first outer coil 24 may comprise from about 1 to as manyas 500 or more “N₁” turns and the second interior coil 26 may comprisefrom about 1 to as many as 1,000 or more “N₂” turns. In a preferredembodiment, the number of “N₂” turns is greater than the number of “N₁”turns. In addition, it is not necessary for the first and second coils24, 26 to be constructed having a discrete number of turns, the coils24, 26 may also be constructed having a partial turn or revolution suchas a half or quarter of a complete turn.

In addition, the conductive filars 30 that form the first outerinductive coil 24 have a filar width that may range from about 0.01 mmto about 20 mm. In a preferred embodiment, the width of the outerinductor coil filars 30 is constant. However, the width of the firstouter inductor conductive filars 30 may vary. The conductive filars 32that form the second interior inductive coil 26 have a preferred widththat ranges from about 0.01 mm to about 20 mm. The second conductivefilar 32 may also be constructed having a constant or variable width. Ina preferred embodiment, the first electrically conductive filars 30 thatform the first outer inductor coil 24, have a width that is greater thanthe width of the second electrically conductive filars 32 that form thesecond interior inductor coil 26. However, it is contemplated that thewidth of the first conductive filars 30 may be about equal to ornarrower than the width of the second electrically conductive filars 32that form the second interior inductor coil 26.

In general, the first outer inductor coil 24 contributes to thereception and/or transmission of higher frequencies in the MHz rangewhereas, the second interior inductor coil 26 contributes to thereception and/or transmission of frequencies in the kHz range. Theincreased perimeter size and typically fewer number of filar turns thatcomprise the first outer inductor coil 24, generally create first coilinductances in the 4.2 pH range, which, thus, provides reception and/ortransmission in the MHz operating frequency range. In contrast, theincreased number of filar turns and smaller coil diameter of the secondinterior inductor coil 26 generally create inductances in the 8.2 pHrange, which provides reception and/or transmission in the kHz operatingfrequency range. Furthermore, by electrically connecting at least thefirst and second inductor coils 24, 26 in series at different locationsthereof, enables the single structure antenna of the present disclosureto operate at multiple frequencies while encompassing reduced surfacearea and a smaller foot print.

Specifically, the single structure antenna of the present disclosurecomprises a plurality of terminal connections that are strategicallypositioned on the first and second inductor coils 24, 26, respectively.This unique antenna design provides for a variety of tunable inductanceswhich, in turn, provides for a variety of selectively tunable operatingfrequencies. In a preferred embodiment, the single structure antenna canbe designed so that it can operate at multiple frequencies and multiplefrequency bands anywhere between about the 1 kHz range to about the 10GHz range. The prior art two structure antenna 10 is not capable ofoperating at such multiple frequencies with such a reduced foot printsize.

FIG. 2 illustrates an example of a three terminal single structureantenna 20 of the present disclosure. As shown in FIG. 2, the firstouter coil 24 is electrically connected in series to the second interiorcoil 26. This electrical connection between the two coils 24, 26combines the inductance contributions of both coils, and portionsthereof, in a reduced foot print. FIG. 2A is an electrical schematicdiagram of the antenna 20 shown in FIG. 2. As shown, the antenna 20comprises three terminals, a first terminal 34 a second terminal 36, anda third terminal 35. As illustrated, the first terminal 34 iselectrically connected to the first outer inductive coil 24, the secondterminal 36 is electrically connected to the second interior inductivecoil 26, and the third terminal 35 is electrically connected to a secondend of the first outer coil 24. Alternatively, the antenna 20 may beconstructed having the first terminal 34 electrically connected to thesecond inductive coil 26 and the second terminal 36 electricallyconnected to the first inductive coil 24.

In a preferred embodiment, the antenna 20 may be constructed with anelectrical switch circuit 37 that enables selection of a desiredinductance and operating frequency. More specifically, the electricalswitch circuit 37 enables the detection and analysis of the electricalimpedance of either or combination thereof of the first and second coils24, 26. Therefore, based on the detection and analysis of the electricalimpedance, an efficient selection of the antenna's operating frequencycan be achieved based on an optimized or desired electrical impedancevalue. In addition, the selection of the terminal connections may bebased on an optimized or desired inductance value at a desired operatingfrequency or frequencies.

As illustrated in FIG. 2A, the switch circuit 37 is electricallyconnected in series between the first and second coils 24, 26. In apreferred embodiment, the switch circuit 37 enables the selection of aconnection between the first and second coils 24, 26, or alternatively,a selection of either of the first or second coils 24, 26 individually.The third terminal 35 is electrically connected at point 33 which is anelectrical junction between the first and second coils 24, 26.

As previously mentioned, the electrical switch circuit 37 preferablycomprises at least one capacitor C₁ having a first capacitance. The atleast one capacitor C₁ is preferably electrically connected along thethird terminal 35. In addition, the switch 37 may also comprise a secondcapacitor C₂ having a second capacitance. The second capacitor C₂ ispreferably connected between point 33 and the second interior coil 26.Inclusion of the at least one capacitor C₁ enables the detection andanalysis of the impedance of either or both coils 24, 26 at an operatingfrequency. In a preferred embodiment, the electrical impedance can bedetermined by the following equation: X=2πfL, where X is the electricalimpedance of the antenna, f is the operating frequency of the antennaand L is the inductance of the antenna.

In a preferred embodiment, the substrate 22 is of a flexible form,capable of bending and mechanical flexure. The substrate 22 ispreferably composed of an electrically insulating material. Examples ofsuch insulative materials may include but are not limited to, a paper, apolymeric material such as polyimide, acrylic or Kapton, fiberglass,polyester, polyether imide, polytetrafluoroethylene, polyethylene,polyetheretherketone (PEEK), polyethylene napthalate, fluropolymers,copolymers, a ceramic material such as alumina, composites thereof, or acombination thereof. In some situations (e.g when the antenna isconstructed using insulated wire such as magnet wire/litz wire orstamped metal), the substrate may be the shielding material.

In a preferred embodiment, at least one of the first, second and thirdterminals 34, 36, 35 of the antenna 20 are electrically connectable toan electronic device 38. The electrical device 38 may be used to modifyand/or condition the electrical power, electrical voltage, electricalcurrent or electronic data signal received or transmitted by the antenna20. The electrical energy received by the antenna may be used todirectly power the electronic device 38. Alternatively, the electricaldevice 38 may be used to transmit electrical power and/or a data signalthereof. The electronic device 38 may comprise, but is not limited to, atuning or matching circuit (not shown), a rectifier (not shown), avoltage regulator (not shown), an electrical resistance load (notshown), an electrochemical cell (not shown) or combinations thereof.

FIG. 3 illustrates an additional embodiment of a three terminal singlestructure antenna 40 of the present disclosure. Similar to the antenna20 embodiment illustrated in FIG. 2, the three terminal antenna 40comprises a first outer coil 42 that is electrically connected in seriesto a second interior coil 44. The electrical connection between the twocoils 42, 44 combines the inductance contributions of each of the coils42, 44 in a reduced size and surface area. The addition of a thirdterminal further enables the antenna 40 to be tuned to a specificfrequency or multiple frequency bands. Thus, by providing multipleconnection points within and between the outer and interior inductorcoils 42, 44 the inductance, and thus, the receiving or transmittingfrequency bands can be instantaneously adjusted without the need to addor remove inductors. The three terminal antenna design enables the firstand second coils 42, 44 to be strategically connected at differentlocations along either or both the first and second coil 42, 44. As aresult, the inductance of the antenna 40 can be modified, i.e.,increased or decreased, without increasing the size of the footprint ofthe antenna. The antenna 40 of the present disclosure efficientlyutilizes space and substrate surface area to increase and/or decreaseinductance therewithin and, thus, custom tune the operating frequency orfrequency band of the antenna 40.

The antenna 40 as shown in FIG. 3 comprises three terminals, a firstterminal 46, a second terminal 48, and a third terminal 50, each havingthree respective terminal connections 52, 54, and 56. Each of theterminals is electrically connected at different terminal connectionpoints of the antenna 40. As shown, the first terminal 46 extends from afirst end 58 of a first trace 60 of the first outer coil 42. The secondterminal 48 extends from a first end 62 of a second trace 64 of thesecond inductor 44. The third terminal 50 extends from a second end 66of the second trace 64 of the second coil 44. Thus, the three terminals46, 48, and 50 provide different connection points between the first andsecond inductor coils 42, 44 and portions thereof. Connecting thevarious terminals in different combinations thus provides the antenna 40of the present disclosure with different adjustable inductances which,in turn, modifies the operating frequency or operating mode of theantenna 40. For example, by electrically connecting the first terminal46 to the second terminal 48, a first inductance may be produced that isgenerally suitable for operation at a first operating frequency.Electrically connecting the first terminal 46 to the third terminal 50produces a second inductance that is generally suitable for operation ata second operating frequency. Electrically connecting the secondterminal 48 to the third terminal 50 produces a third inductance that isgenerally suitable for operation at a third operating frequency. Each ofthe inductances that are capable of being generated by the antenna ofthe present disclosure is preferably different from each other.Furthermore, it is contemplated that the antenna may be able toinstantaneously switch from one inductance value to another, therebyinstantaneously changing the antenna's operating frequency.

FIG. 3A illustrates an electrical schematic diagram of the threeterminal antenna 40 illustrated in FIG. 3. As shown, connecting thefirst terminal 46 and the third terminal 50 provides a connection to thefirst outer inductor coil 42 having “N₁” number of turns. Connecting thesecond terminal 48 to the first terminal 46 provides a connection to thesecond interior inductor coil 44 having “N₂” number of turns. Lastly,establishing a connection between the second and third terminals 48, 50provides an electrical series connection to both the first outerinductor coil 42 and the second interior inductor coil 44 having“N₁”+“N₂” turns. More specifically, FIG. 3A illustrates an embodiment inwhich the first inductor coil 42 is electrically connected in serieswith the second inductor coil 44. As shown, the first terminal 46 iselectrically connected to the first end 58 of the first outer inductorcoil 42. The second terminal 48 is electrically connected to the firstend 62 of the second inductor coil 44 at an electrical junction 68distal of the first inductor coil first end 58. As illustrated, thethird terminal 50 is electrically connected to a second end 70 of thefirst inductor coil 42.

In a preferred embodiment, the three-terminal antenna design shown inFIGS. 3 and 3A enables the operation of the antenna in three differentoperation modes. As defined herein, an operation mode is an operatingfrequency band width. Such modes may include, but are not limited to theQi, PMA and Rezence wireless standard frequencies. Table I shown below,details an example of the different terminal connection configurationsand how they affect the operation mode of the antenna. Morespecifically, Table I illustrates various examples of how the operatingfrequency of the antenna may be changed by connecting various terminalconnections together. It is noted that the operating frequenciesdetailed in Table I are examples and that the operating frequency bandsmay be custom tailored to meet specific requirements. Such customizationcan be achieved through designing each coil with a specific number ofturns, a specific trace width, and terminal location points on each ofthe first and second coils.

TABLE I Terminal Mode Operating Frequency Connections 1 100-250 kHz (Qiand/or PMA) 1 and 2 1 6.78 MHz (A4WP) 1 and 3 2 13.56 MHz (NFC/RFID/ 1and 3 Proprietary power and data) 2 100-250 kHz (Qi and/or PMA) 2 and 33 250-500 kHz (PMA and/or, 2 and 3 proprietary power and data)

While FIGS. 3 and 3A illustrate a specific example of connecting threeterminals to the respective ends of the first and second inductor coils42, 44, it is further contemplated that these connections may bepositioned at various electrically conductive points along the first andsecond conductive traces 60, 64 of the first and second inductor coils42, 44. In addition, it is contemplated that additional terminalconnections may be positioned along the first and second 42, 44 inductorcoils of the antenna 40, to further provide customized inductances and,thus, provide customized operating frequencies of the antenna 40. Ingeneral, establishing an electrical connection with an inductor coil ormultiple inductor coils having an increased number of turns increasesthe inductance that results in an antenna that more suitable to receiveor transmit lower frequency signals. Likewise, establishing anelectrical connection with an inductor coil or multiple inductor coilshaving a decreased number of turns decreases the inductance andtherefore results in an antenna that is more suitable to receive ortransmit higher frequency signals.

Similar to the two terminal antenna illustrated in FIGS. 2 and 2A, thethree terminal antenna may be electrically connected to an electricaldevice 38. The electrical device 38 may be designed to condition ormodify electrical power and/or an electrical signal, such as a digitaldata signal. Alternatively, the electrical device 38 may directlyreceive or transmit the electrical power and/or data signal. Theelectronic device 38 may comprise, but is not limited to, a tuning ormatching circuit (not shown), a rectifier (not shown), a voltageregulator (not shown), an electrical resistance load (not shown), anelectrochemical cell (not shown) or combinations thereof. In addition tomodifying or conditioning a received electrical voltage, electricalcurrent, or digital signal, the electronic device 38 may also be used tomodify or condition an electrical voltage, electrical current, ordigital signal that is being transmitted by the antenna 40.

FIGS. 3B and 3C illustrate an embodiment of a multiple layer threeterminal antenna 72. In a preferred embodiment, the single structureantenna of the present disclosure may comprise a plurality of two ormore substrate layers 22 that are positioned in a parallel orientationto each other. In addition, at least one electrically conductive traceis positioned along an exterior surface of the substrates that comprisethe antenna 72. The filar or filars may be orientated such that at leastone inductor coil is disposed along a top surface of one or more of thesubstrates. The substrates that comprise the antenna are preferablyoriented in the same orientation such that the bottom surface of a firstsubstrate is positioned above the top surface of a second substrate.

In addition, at least one via may be provided to establish an electricalconnection between the various substrate layers. In a preferredembodiment, the at least one via provides an electrical connectionbetween filars or portions of filars that comprise an inductor coil orcoils at different substrate layers. As defined herein a “via” is anelectrical connection between two or more substrate layers. A via maycomprise a wire, an electrically filled through-bore or electricallyconductive trace.

Specifically, FIGS. 3B and 3C illustrate the first and second layers,respectively of a two layer three terminal single structure antenna.FIG. 3B illustrates an embodiment of a first or lower layer 74 of theantenna 72 of the present disclosure. As shown, the first layer 74comprises a first outer inductive coil 76 that is electrically connectedin series to a second interior inductive coil 78.

In a preferred embodiment, as illustrated in FIG. 3B, the first terminal46 is electrically connected in parallel to two traces or filars,thereby creating a bifilar connection 80 that comprises the firstinductor coil 76. It is noted that two or more adjacent electricallyconductive traces or filars that comprise an inductive coil may beconnected in parallel. In general, connecting two or more adjacenttraces or filars reduces electrical resistance, particularly theequivalent series resistance (ESR) of the antenna and as a result,improves the quality factor of the antenna.

As shown in FIG. 3B, the first inductor coil 76 is electricallyconnected in series to the second interior inductor coil 78 that ispositioned within an inner perimeter formed by the first inductor coil76. As shown, a second end 82 of the first inductor coil 76, located atan inner most end of the coil 76 is electrically connected to a firstend 84 of the second inductor coil 78. The first end 84 of the interiorinductor coil 78 is disposed at the end of an outer most filar track ofthe second inductor coil 78. The second inductor coil 78 terminates at asecond inductor coil second end 86 which is disposed at an inner mostlocation of the second inductor coil 78.

FIG. 3C illustrates an embodiment of a second upper substrate layer 88of the antenna 72 of the present disclosure. The second layer 88 ispreferably positioned directly above the first lower substrate 74. Thesecond layer 88 comprises a third outer inductor coil 90 that iselectrically connected in series to a fourth interior inductor coil 92.In a preferred embodiment, the respective first and third coils 76, 90and the second and fourth coils 78, 92 of the first and second layers74, 88 may be positioned about their respective substrates in a parallelrelationship. In addition, the respective first and third coils 76, 90and the second and fourth coils 78, 92 of the first and second layers74, 88 may be in a similar position about their respective substratesurfaces and may comprise the same number of turns with similar tracewidths. Alternatively, the respective first and third coils 76, 90 andthe second and fourth coils 78, 92 of the first and second layers 74, 88may be positioned at different locations relative to their specificsubstrate surfaces and they may have differing number of turns withdiffering trace widths.

Similar to the first layer 74, the first terminal 46 of the second layer74 is electrically connected in parallel to two adjacently positionedtraces or filars, thereby creating a bifilar connection at a first end94 of the third inductor coil 90. This bifilar connection comprises theelectrical trace pattern of the third inductor coil 90, extending aroundthe third coil 90 and ending at a second end 96 thereof. Furthermore,the third inductor coil 90 is electrically connected in series to thefourth interior inductor coil 92 positioned within the inner perimeterof the third inductor coil 90 at a third inductor coil second end 96which is disposed at an interior location of the third inductor coil 90.The fourth inductor coil 92 is electrically connected to the thirdinductor coil 90 at a first end 98 of the interior inductor coil whichis disposed at an outer most filar track of the fourth inductor coil 92.In addition, as illustrated in FIG. 3C, the second upper layer 88 alsocomprises the second and third terminal connections 48, 50. In apreferred embodiment, the second terminal 48 is electrically connectedat a second end 100 of the fourth inductor coil 92 positioned at aninner most location of the fourth coil 92. In addition, the length ofthe second terminal 48 is electrically isolated from each of the filartracks that comprise the third and fourth inductor coils 90, 92. Thethird terminal 50 is provided on the second upper layer 88. As shown,the third terminal 50 is electrically connected to the bifilar track 94that is disposed at the inner most location of the third outer inductorcoil 90.

Furthermore, a via 102 or a plurality of vias 102, are preferablypositioned between two or more substrate layers 74, 88 that comprise thesingle structure antenna 72 of the present disclosure. More preferably,the at least one via 102 provides a shunted electrical connectionbetween different locations between the respective first and thirdinductor coils 76, 90 or the second and fourth inductor coils 78, 92 tominimize electrical resistance which may adversely affect electricalperformance and quality factor.

In a preferred embodiment, a plurality of shunted via connections arepositioned between the upper and lower layers to electrically isolateportions of the second and third terminals 48, 50, thereby enabling theterminals to “overpass” the conductive traces of the respective coils.More specifically, to create an “overpass” a plurality of vias 102 maybe positioned on respective left and right sides of a trace 104 of theterminal. The plurality of vias 102 positioned on the respective leftand right sides of the terminal line 104 of the terminal thus formelectrical paths underneath the terminal trace 104, thereby electricallyisolating the terminal trace 104 by “bypassing” the portion ofconductive traces on which the terminal lead 104 is positioned. Inaddition, the plurality of shunted vias 102 may also create anelectrical path that bypasses at least a portion of the terminal lead104. In this embodiment, each of the plurality of vias 102 arepositioned in opposition to each other on respective left and rightsides of the terminal lead 104.

FIG. 3D illustrates a magnified view of an example of a plurality ofshunted via connections between a portion of the first inductor coil 76that is disposed on the lower first substrate layer 74 and the thirdinductor coil 90 that is disposed on the upper second substrate layer88. As shown, a plurality of via connections is shown between inductorcoils that are disposed on the respective upper and lower substratelayers 74, 88. More specifically, as shown in the embodiment of FIG. 3D,there are four vias 102 positioned along each filar tracks besides eachof the respective right and left sides of the terminal line 104. In apreferred embodiment, the via connections provide a shunted electricalconnection that by passes under the terminal line 104. Thus bypositioning a plurality of vias adjacent the respective sides of theterminal line 104, an electrical connection can be provided thatbypasses the terminal line 104 of the terminal thereby keeping theterminal trace 104 electrically isolated from the conductive traces itpasses through. Furthermore, by providing a plurality of vias 102positioned along each of the filar tracks that comprise the inductorcoil, various electrical connections can be made which can furthertailor the inductance and resulting operating frequency of the singlestructure antenna of the present disclosure. For example, variouselectrically isolated terminal connections can be positioned throughoutthe inductor coils thus establishing further customized inductances andoperating frequencies.

FIG. 3E illustrates an alternative embodiment of a single structureantenna 106 in which respective first and second inductive coils 108,110 comprise a single filar pattern. As shown the first, second andthird terminals 46, 48, and 50 are respectively connected to a singlefilar that comprises the first and second inductor coils 108, 110. Whileit is preferred to connect the respective terminals to multiple filars,such as the first terminal connection shown in FIGS. 3B and 3C, tominimize electrical resistance, it may be necessary to provide anelectrical connection to a single filar to achieve a desired inductancein a relatively small space and/or surface area. In general, having anelectrical parallel connection to two or more adjacently positionedfilars reduces electrical resistance which in turn increases the qualityfactor of the antenna.

FIG. 3F illustrates a magnified view of the terminal connectionsillustrated in FIG. 3E. As shown, the terminal traces of the second andthird terminals 48, 50 are electrically isolated as they effectivelybypass over the electrically conductive the filar tracks that comprisethe inductor coil. Via connections 103 provided on both sides of therespective terminal lines 104 provide an electrical connection thatbypasses the terminal lines thereby electrically isolating the terminallines from the filar lines of that comprise the inductor coil. As shown,a plurality of vias 102A are positioned on the right side of theterminal lead 104 of the third terminal 50, vias 102B are positioned tothe left and right of the terminal traces 104 of respective thirdterminal 50 and second terminal 48 and vias 102C are positioned to theleft of the terminal trace of the first terminal 48.

In addition to the two and three terminal antennas illustrated in thepresent application, it is further contemplated that a single structureantenna may comprise four or more terminal connections. FIG. 4illustrates an electrical circuit diagram of an embodiment of a fourterminal antenna 112 of the present disclosure. As illustrated, thefirst terminal 46 is electrically connected to the first end 58 of thefirst outer inductor coil 42. The second terminal 48 is electricallyconnected to the first end of the second inductor coil 44. The thirdterminal 50 is electrically connected to the second end 70 of the firstinductor coil 42. In addition, a fourth terminal 114 is electricallyconnected to a second point 116 along the electrically conductive trackof the first inductor coil 42. The fourth terminal connectioneffectively shortens the length of the first inductor coil 42 and/or thenumber of turns between electrical connections thereby providing anadditional terminal connection which can be selected to adjust theinductance and operating frequency of the antenna.

Table II shown below, details the inductance and resulting operatingfrequency of an exemplar three and four terminal connection antennasillustrated in FIGS. 2, 2A, 3, 3A, 4 and 4B. It is noted that theinductance may be increased or decreased by modifying the number ofturns of at least one of the first and second inductor coils.

TABLE II Terminal Antenna Connection Operating Inductance Quality ConfigConfig N₁ N₂ Frequency (μH) Factor 4 1 and 2 3 0 6.78 MHz 0.84 >110Terminal 4 3 and 4 0 14 100-300 kHz 6.7 >20 Terminal 3 1 and 2 3 14 6.78MHz 0.84 >110 Terminal 3 1 and 3 3 17 100-300 kHz 7.5 ~17.5 Terminal 3 2and 3 3 14 100-300 kHz 6.7 >20 Terminal

As the table above illustrates, by establishing different electricalconnection points along the coils that comprise the antenna, providesfor a wide range of inductances, operating frequencies and frequencybands. As shown above, by increasing or decreasing the total number ofturns, i.e. by selectively connecting different locations of theelectrically connected the first and second inductor coils, and portionsthereof affects the resultant inductance of the antenna.

In a preferred embodiment, the electrical or electronic device 38 may bea selection circuit 118 electrically connected to the single structureantenna of the present disclosure. Specifically, the selection circuit118 is electrically connected to at least two of the terminals thatcomprise the antenna. The selection circuit 118 actively monitors andmeasures the electrical impedance at the respective antenna terminalsand combinations thereof. Thus, when the electrical impedance ismeasured to be at, above, or below a certain threshold electricalimpedance or band of electrical impedances, the selection circuit 118 iscapable of connecting or disconnecting the various terminals thatcomprise the antenna to achieve a desired frequency band. In a preferredembodiment, the selection circuit 118 comprises at least one capacitorhaving a capacitance C₃. The capacitance of the selection circuit isselected to activate a switching mechanism between antenna terminals byproviding a high impedance path or a low impedance path, depending onthe frequency of operation. In addition, the selection circuit 118 mayalso be able to actively connect and/or disconnect various regions orspecific locations along the inductance coils that comprise the singlestructure antenna. In an embodiment, the selection circuit 118 operatesby selecting an inductor coil, portion of an inductor coil, orcombinations thereof, having the lowest electrical impedance.Alternatively, the selection circuit 118 may be designed to activelyswitch between terminals at a specific electrical impedances or range ofelectrical impedances. For example, the selection circuit 118 maymeasure the electrical impedance at various terminal connections anddetermine that based on the value of the capacitance C₃ within theselection circuit 118 to connect terminals 1 and 3 instead of terminals1 and 2 for example.

Consider, for example, a multi-mode antenna system wherein a firstfrequency mode is operating in the frequency range of f₁+/−Δf₁, and asecond frequency mode is operating at f₂+/−Δf₂, wherein f₁ is theresonating frequency of the first outer inductor coil, Δf₁ is thebandwidth of the resonating frequency of the first outer inductor coilformed by the first terminal 46 and the third terminal 50 (FIG. 3E), f₂is the resonating frequency of the second interior inductor coil, andΔf₂ is the bandwidth of the resonating frequency of the second interiorinductor coil formed between the first and second terminals 46, 48 (FIG.3E), provided the following conditions (A, B, and C) are true for theexemplar antenna.

Example Conditions

A. f₁≧10 f₂,

B. Δf₂≦0.5 f₂

C. Δf₁≦f₁/50

The selection circuit may be configured to select a desired antennaimpedance Z₂, at a desired antenna operating frequency f. For example,given the parameter equations as shown below, where C₃ is thecapacitance value of the selection circuit 118 for a desired antennaoperating frequency, f (e.g. f=f₁±Δf₁ or f=f₂±Δf₂) and in which theimpedance of the antenna is multiplied by a constant such as 1, 2, or 5.Thus, the selection circuit 118 can be designed such that the terminalconnections are made at a certain impedance threshold value at aspecific frequency or frequency band which may be determined by amultiplier constant.

$\frac{1}{2\pi \; f\mspace{14mu} C_{3}} < {{Constant} \times {{Z\; 1\mspace{14mu} {or}\mspace{14mu} 2}}}$

In general, the greater the difference in electrical impedance, thebetter discrimination in coil selection, thus the multiplier constantsuch be selected to create a discriminating electrical impedance thatmay be used to modify the operating frequency of the antenna. Thus,provided a capacitance value C₃, the selection circuit may choosebetween the lower of the electrical resistance of the first inductorcoil Z₁ and the electrical resistance of the second inductor coil Z₂. Inthe example, if

$\frac{1}{2\pi \; f\mspace{14mu} C_{1}}$

is lower than Z₂, the selection circuit may actively choose the terminalconnections for the first inductor coil. An exemplary situation is whenthe higher frequency range conforms to a single mode, the Rezencewireless charging standard operating at a frequency f₁ of about 6.78 MHzwith a bandwidth of +/−15 kHz, while the lower frequency range conformsto two modes, i.e., the Qi standard operating between 100 kHz and 205kHz and the PMA standard operating between 100 kHz and 350 kHz. In thiscase, if the first outer inductor coil is selected, then the antennawill actively receive or transmit in the Rezence mode at an operatingfrequency of about 6.78 MHz.

In addition to the number of turns and various lengths of theelectrically conductive filars of the respective inductor coils thatcontrol the inductance and operating frequency of the antenna of thepresent disclosure, the quality factor of the single structure multiplemode antenna of the present disclosure can be significantly affected bythe length and position of a gap 120 of space disposed between adjacentfirst and second inductor coils such as the first and second inductorcoils 76, 78 and/or the third and fourth inductor coils 90, 92.

As will be described herein, the single structure multiple mode antenna20, 40, 72, 106, 112 of the present disclosure is preferably designedwith a high quality factor (QF) to achieve efficient reception/transferof electrical power and/or an electrical data signal. In general, thequality factor of the antenna is increased by reducing the intrinsicresistive losses within the antenna, particularly at high operatingfrequencies of at least 300 kHz.

The quality factor is the ratio of energy stored by a device to theenergy lost by the device. Thus, the QF of an antenna is the rate ofenergy loss relative to the stored energy of the antenna. A sourcedevice carrying a time-varying current, such as an antenna, possessesenergy which may be divided into three components: 1) resistive energy(W_(res)), 2) radiative energy (W_(rad)) and 3) reactive energy(W_(rea)). In the case of antennas, energy stored is reactive energy andenergy lost is resistive and radiative energies, wherein the antennaquality factor is represented by the equationQ=W_(rea)/(W_(res)+W_(rad)).

In near field communications, radiative and resistive energies arereleased by the device, in this case the antenna, to the surroundingenvironment. When energy must be transferred between devices havinglimited power stores, e.g., battery powered devices having sizeconstraints, excessive power loss may significantly reduce the devices'performance effectiveness. As such, near-field communication devices aredesigned to minimize both resistive and radiative energies whilemaximizing reactive energy. In other words, near-field communicationsbenefit from maximizing Q.

By example, the efficiency of energy and/or data transfer betweendevices in an inductively coupled system is based on the quality factorof the antenna in the transmitter (Q₁), the quality factor of theantenna in the receiver (Q₂), and the coupling coefficient between thetwo antennas (κ). The efficiency of the energy transfer varies accordingto the following relationship: effακ²Q₁Q₂. A higher quality factorindicates a lower rate of energy loss relative to the stored energy ofthe antenna. Conversely, a lower quality factor indicates a higher rateof energy loss relative to the stored energy of the antenna. Thecoupling coefficient (κ) expresses the degree of coupling that existsbetween two antennas.

Further, by example, the quality factor of an inductive antenna variesaccording to the following relationship:

$Q = \frac{2\pi \; {fL}}{R}$

where f is the frequency of operation, L is the inductance, and R is thetotal resistance (ohmic+rediative). As the quality factor is inverselyproportional to the resistance, a higher resistance translates into alower quality factor. Thus, the antenna of the present disclosure isdesigned to decrease the electrical resistance and, therefore, increasethe quality factor.

Specifically, the single structure multiple mode antenna of the presentdisclosure is designed with a gap of space 120 positioned betweenadjacently positioned inductor coils such as the first and secondinductor coils 24, 26. This gap 120 preferably reduces the proximityeffect between adjacently positioned inner and outer coils, such as 76,78 (FIG. 3B) and 90, 92 (FIG. 3C). As defined herein, “proximity effect”is the resultant increase in electrical resistance that occurs when twowires carrying alternating current, are positioned next to each other.More specifically, the proximity effect relates to the effect that onecurrent carrying filament has on an adjacent current carrying filamentwhen time-varying current is propagating through at least one of theconductive filaments. The magnetic field generated by one filamentcreates a field that opposes the current in the adjacent filament,thereby creating additional alternating current (AC) electricalresistance. This effect increases with frequency according to Faraday'slaw. In other words, when two electrically conductive wires arepositioned next to each other, the magnetic field of one wire induceslongitudinal eddy currents in the other adjacent wire. These eddycurrents flow in long loops along the wire in the opposite direction asthe main current. Thus, these eddy currents reinforce the main currenton the side facing away from the first wire, and oppose the main currenton the side facing the first wire. The net effect is a redistribution ofthe current in the cross section of the wire into a thin strip on theside facing away from the other wire. Since the current is concentratedinto a smaller area of the wire, the resistance is increased.

The proximity effect has a significant effect on the quality factor ofthe antenna design. The applicants have discovered that the proximityeffect can be greatly reduced by increasing the gap or distance 120between the first outer and second interior inductor coils. However,increasing the gap 120 between these coils such that the proximityeffect is negligible appreciably increases the foot print of the antennawhich is not desired.

Therefore, a balance between the strength of the proximity effect andits effect on the quality factor and foot print size must be optimallyachieved. In general, the applicants have discovered that by providingthe gap 120 having a distance of about 0.2 mm reduces the magnetic fieldstrength by about 50%, and designing the gap 120 with a distance ofabout 1 mm reduces the magnetic field strength by about 90%. It iscontemplated that the gap 120 may range from about 0.05 mm to about 10mm.

Another important consideration is the operating frequency of theantenna. In general, AC electrical resistance increases with increasingmagnetic field strength. This increase in AC electrical resistance isabout proportional to the magnetic field strength. This is due to thegenerally increased proximity effect at increased operating frequencies.In general, the increase in proximity effect can be mathematicallyrepresented by the strength of the magnetic field H of an adjacent filarmultiplied by the operating frequency.

For example, to obtain a similarly equal reduction of proximity effectfor a first antenna operating at 6.78 MHz in comparison to a secondantenna operating at 200 kHz, the magnetic field strength generated bythe first antenna is required to be reduced by about a factor of 34(6.78 Mhz/200 kHz). Therefore, to obtain a similar reduction in ACelectrical resistance due to the proximity effect, between the firstantenna operating at 6.78 MHz and the second antenna operating at 200kHz, would thus require a gap of about 0.2 mm between adjacent coiltraces for the second antenna operating at 200 kHz, and a gap greaterthan 5 mm between adjacent coil traces for the first antenna operatingat 6.78 MHz.

The applicants have thus discovered that designing the gap 120 having adimension of 0.5 mm, or greater, between the first outer and secondinterior coils significantly reduces the proximity effect to anegligible amount for frequencies between about 100 to about 200 kHz.Furthermore, the applicants have discovered that designing the gap 120having a distance of about 1 mm for frequencies between about 200 toabout 400 kHz, or greater, is more preferred. In some cases, where theoverall allowable surface area is large, for example, when the totalnumber of turns of the first outer and second interior inductor coils isgreater than 100 and the frequency is around 6.78 MHz to 13.56 MHz, thisdistance can be as great as 10 mm. In general, a gap distance 120 ofabout 10 mm effectively reduces the magnetic field strength and theproximity effect by about 99 percent.

Table III shown below, illustrates the effect of the gap size on theelectrical resistance and resulting quality factor. Specifically,examples 1-4 are of a three terminal single structure multi-mode antennahaving different gap sizes between the first outer and second interiorcoils. As illustrated in the table, increasing the size of the gap toabout 1.8 mm, increases the quality factor by about 35% in comparison toa gap size of 0.2 mm of the antenna constructed in example 4. If alarger footprint is possible for the entire antenna structure, this gapsize may be further increased greater than 5 mm which results in anincrease in quality factor of about 42% in comparison to the example 4antenna which constructed with a gap size of about 0.2 mm.

For example, a system with a coupling coefficient of about 0.05 for asystem operating at 6.78 MHz, and using the same coil configuration forthe respective receiving and transmitting antennas with a 1.8 mm gapwill yield an antenna to antenna efficiency improvement of about 16%. Inaddition, using a gap size greater than 5 mm would yield an antenna toantenna efficiency improvement of about 18% given the equation belowwhere K is the coupling coefficient between a transmitting and receivingantenna, Q₁ is the quality factor of the receiving antenna, and Q₂ isthe quality factor of the transmitting antenna. As defined herein,“antenna to antenna efficiency” is the percentage of electrical energyreceived by a receiving antenna that was originally transmitted by acorresponding transmitting antenna.

${Eff} = \frac{\kappa^{2}Q_{1}Q_{2}}{\left( {1 + \sqrt{1 + \left( {\kappa^{2}Q_{1}Q_{2}} \right)}} \right)^{2}}$

TABLE III Gap Freq. Inductance Resistance Quality Example Size (MHz)(μH) (ohms) Factor 1 >5.0 mm  6.78 3.1 1.30 101.6 2 1.8 mm 6.78 3.1 1.3796.4 3 1.0 mm 6.78 3.1 1.57 84.1 4 0.2 mm 6.78 3.1 1.85 71.4

It is important to note that the magnetic field strength is directlyproportional to the strength of the electrical current being propagatedthrough an adjacent filar. For example, given the same operatingfrequency, the strength of the proximity effect generated from a filarwith 1 A of electrical current propagated therewithin is about 100 timesgreater than if the electrical current is at 10 mA.

FIG. 5 illustrates an embodiment of an inductor coil 121 which comprisesa conductive filar 123 having a variable filar width. As shown, at leastone of the inductor coils that comprise an antenna may be constructedhaving a filar width that ranges from about 5 mm to about 0.01 mm, morepreferably from 0.55 mm to about 0.2 mm. In the preferred embodimentshown, the inductor coil is constructed having an outer filar width at afirst coil end 122 that ranges from about 10 mm to about 1 mm thatprogressively becomes narrow as the filar extends towards the center ofthe inductor 121. In a preferred embodiment, the filar width at thesecond end 124 may range from about 5 mm to about 0.01 mm. Such thinningof the filar width is desirous to provide an additional number of turnswithin a smaller surface area, thereby leading to an inductance valuethat is higher than what would have been achieved with wider traces forall turns. Furthermore, increasing the number of turns reduces thecross-sectional area of the filament utilized by the current due to thenet proximity effects of the multitude of filaments. Therefore it ispossible that a wide trace may have regions through which the currentdensity is significantly reduced. By designing the coil in a manner ofreducing the trace widths, the area utilization is maximized.Utilization of cross-sectional area is reduced due to proximity effectwith increased frequency and a greater number of traces.

Constructing a coil with variable trace widths can significantlyincrease the inductance of the antenna. For example, two antennas havingthe same coil outer dimension of 34.5 mm×27 mm and an inner dimension of15.4 mm×7.9 mm were constructed. The first antenna was constructed with13 turns at a constant trace width of about 0.55 mm and a constant gapwith between traces of about 0.2 mm. In comparison, the second antennacoil was constructed with 13 turns and a constant gap width of about 0.2mm between adjacent traces of the coil. However, the second antenna wasalso constructed having a variable trace width that ranged from 0.55 mmto about 0.2 mm in the interior of the coil. The inductance of theantenna of design 1 having a constant trace width was measured to beabout 4.2 μH. In contrast, the inductance of the antenna of design 2with the variable trace width was measured to be about 8.2 μH, aboutdouble the inductance of the antenna of the first design with the sameoverall dimensions.

In a preferred embodiment, the quality factor may also be increased byincorporating various materials or structures that prevent or block themagnetic fields that cause the proximity effect that thus results inincreased electrical resistance of adjoining conductive filars andultimately results in a decreased quality factor. One such shieldingmaterial are ferrite materials which have a high permeability thateffectively shields inductor coils from magnetic fields generated froman adjacent inductor coil or coils. Thus, by shielding the inductivecoil from the magnetic field generated from another coil, reduces theproximity effect and, thus, increases the quality factor of the antenna.

The shielding material preferably has the primary function of providinga low reluctance path to magnetic field lines thereby reducing theinteraction of the magnetic fields with other metallic objects,especially objects (e.g. batteries, circuit boards) placed behind thecoil assembly. A second function of the shielding material is preferablyto boost the inductance of the coil and, simultaneously, to increase thecoupling between the transmitter coil assembly and the receiver coilassembly. The latter directly affects the efficiency of power transfer.The third ancillary benefit is that it may also improve the QualityFactor of the coil antenna if the loss tangent of the magnetic materialis sufficiently small. As defined herein, “reluctance” is the resistanceto a magnetic flux.

FIGS. 6A, 6B, 6C, 6D, and 6E are cross-sectional views illustratingvarious embodiments in which an inductor coil having an electricallyconductive trace 30, 32 of a single structure multi-mode antenna of thepresent disclosure may be constructed using materials that shield theconductive traces, i.e., wires of the coils 24, 26 from magnetic fields.Such shielding materials may include, but are not limited to, zinccomprising ferrite materials such as manganese-zinc, nickel-zinc,copper-zinc, magnesium-zinc, and combinations thereof. These and otherferrite material formulations may be incorporated within a polymericmaterial matrix so as to form a flexible ferrite substrate. Examples ofsuch materials may include but are not limited to, FFSR and FFSX seriesferrite materials manufactured by Kitagawa Industries America, Inc. ofSan Jose Calif. and Flux Field Directional RFIC material, manufacturedby 3M™ Corporation of Minneapolis Minn.

As shown in the various embodiments, three different such materials, afirst material 126, a second material 128 and a third material 132, eachhaving a different permeability, loss tangent, and/or magnetic fluxsaturation density may be used in the construction of the singlestructure antenna of the present disclosure. In a preferred embodiment,the first material 126 may comprise at least one of the FFSX series offerrite materials having a permeability of about 100 to about 120 acrossa frequency range of at least 100 kHz to 7 MHz. The second material 128may comprise the RFIC ferrite material having a permeability of about 40to about 60, and the third material 130 may also comprise a ferritematerial or combinations thereof, as previously mentioned. In apreferred embodiment, the first 126, second 128, or third 130 materialsmay comprise a permeability greater than 40. More preferably, the first126, second 128, or third 130 materials may comprise a permeabilitygreater than 100. The magnetic flux saturation density (Bsat) is atleast 380 mT.

FIG. 6A shows an embodiment in which the conductive segments 30, 32 arepositioned directly on an exterior surface of the ferrite materials. Asshown, the first and second ferrite materials 126, 128 serve assubstrate layers on which the conductive traces 30, 32 are positioned.The third ferrite material 130 is preferably positioned within a centrallocation between the coil winding. Note that each conductive segment 30,32 could represent multiple traces of the coil turns. Specifically, asshown, first and second outer segments 131, 135 of the conductive traces30, 32 are positioned directly on the surface of a first layer of thefirst ferrite material 126 and the third and fourth inner segments 137,139 of the conductive trace 30, 32 are positioned directly on thesurface of a second layer of the second ferrite material 128. The secondlayer of the second ferrite material 128 is positioned on top of thefirst layer of the first ferrite material 126. A third layer of thethird ferrite material 130 is positioned directly on the second layer ofthe second ferrite material 128. In a preferred embodiment, the first,second and third layers of the different ferrite materials 126, 128, and130 are positioned such that magnetic fields 132 generated by theconductive trace 30, 32 are absorbed by the ferrite materials.Furthermore, the selection of the ferrite material may be based on thematerial used to construct the conductive lines as well as the amount ofthe current or voltage flowing therethrough.

In a preferred embodiment, the various shielding materials andstructures could be used to create a hybrid shielding embodiment. In ahybrid shielding embodiment, the various shielding materials arestrategically positioned to improve the performance of the multipleinductor coils which resonate at differing frequencies. Thus, theshielding materials are positioned to enhance the multi-mode operationof the antenna 10. For example, utilizing a ferrite material having anincreased permeability of about 100 to 120, such as the FFSX seriesmaterial may be used to optimally shield a coil resonating at 6.78 MHzwithout degrading the performance of the other coil resonating at alower frequency range of 100 kHz to about 500 kHz. Likewise, utilizationof a ferrite material having a lower permeability such as from about 40to about 60, like the RFIC material, is preferred because it enhancesoperation of a coil resonating in the lower kHz frequency region withoutdegrading performance of the higher MHz resonating coil.

In addition to the specific shielding material, the positioning of theshielding material is also important to the optimal operation of themulti-mode single structure antenna of the present disclosure. Forexample with reference to FIGS. 6A through 6E, it may be preferred toposition the higher permeability ferrite material near the higherresonating coil, such as the relative location of the first material 126as shown in FIGS. 6A-6E. Similarly, it may be beneficial to position thelower permeability material near the coil that is resonating in the kHzrange such as the location of the second material 128 The third material130 could be a material that has similar material properties as thesecond material 128 or, alternatively, the third material 130 could be aferrite material that has a high magnetic saturation that preserves themagnetic performance of the other materials in the presence of atransmitting that comprise a magnet; it also acts as an attractor tohelp affixing to transmitting coils that comprise a magnet.

FIG. 6B illustrates a different embodiment of the construction of theantenna of the present disclosure in which the second ferrite material128 is positioned within a cavity formed within the first material 126.In addition, the height of the second ferrite material layer 128 isgreater than the height of the first layer of the first ferrite material126.

FIG. 6C illustrates another alternative embodiment in which the secondferrite material 128 is positioned within a cavity of the first ferritematerial 126. However, in contrast to the embodiments shown ion FIGS. 6Aand 6B, the height of the respective first and second ferrite materiallayers are about the same. FIG. 6D shows yet another embodiment in whichthe third ferrite material 130 may be positioned within a second cavitypositioned within the second material layer 128. In addition, the secondmaterial 128 is positioned within the first cavity formed within thefirst layer of the first material 126. Lastly, FIG. 6E illustrates afourth embodiment in which all three materials 126, 128 and 130 arepositioned such that they are of about the same height. Specifically asshown, the third material 130 is positioned within the second cavity ofthe second material layer 128, the second material 128 is positionedwithin the first cavity of the first material layer 126 with all threematerial layers 126, 128, 130 being of about equal height. Therefore,the various layers of ferrite material may be positioned at differentheights relative to each other such that magnetic fields 132 generatedby adjacent conductive lines are optimally adsorbed by the ferritematerials.

In addition to utilizing three ferrite materials as previouslydiscussed, it is contemplated that mixtures or compounds of variousferrite materials may be used to further custom tailor the desiredpermeability. Furthermore, the various layers may be composed of ferritematerial mixtures and alloys. It is also noted that FIGS. 6A-6Crepresents specific embodiments in which ferrite materials may bepositioned within the structure of the antenna of the presentdisclosure. It is contemplated that the various first, second, and thirdferrite materials 126, 128, 130 can be interchangeably positionedthroughout the structure of the antenna to custom tailor a desiredresponse or create a specific magnetic field profile.

It will be appreciated that the multi-mode single structure antenna ofthe present application may be formed or made by any suitable techniquesand with any suitable materials. For example, the antenna coils maycomprise suitable metals or metal containing compounds and/orcomposites, conductive polymers, conductive inks, solders, wire, fiber,filaments, ribbon, layered metal combinations and combinations thereofbe used as conductive materials. Suitable fabrication techniques may beused to place conductors on/in a substrate, including, but not limitedto, printing techniques, photolithography techniques, chemical or laseretching techniques, laser cladding, laser cutting, physical or chemicalvapor deposition, electrochemical deposition, molecular beam epitaxy,atomic layer deposition, stamping, chemical processing, and combinationsthereof. It may also be suitable to fabricate the multi-modesingle-structure antenna with wire-winding techniques leveraging magnetwires, coated wires, litz wires or other wires used by those skilled inthe art. Electrical property enhancement, i.e., enhancement ofelectrical conductivity and substrate dielectric constant may also beused to achieve the desired properties for a specific application. Forexample, enhancement of electrical conductivity may be achieved throughion implantation, doping, furnace annealing, rapid thermal annealing, UVprocessing and combinations thereof.

FIG. 7 illustrates a flow chart illustrating an embodiment of a methodof fabricating a single structure multi-mode antenna of the presentdisclosure. As shown in the flow chart, in a first step 200 a substrate22 may be provided. In a second step 202 the first coil 24 is formed.The first coil 24 may be formed on a surface 28 of a substrate 22 oralternatively, the first coil 24 may be formed without a substrate 22using at least any of the fabrication techniques previously discussed.In a third step 204, the second coil 26 is formed such that iselectrically connected to the first coil 24. Like the previous step 202,the second coil 26 may be formed on a surface 28 of the substrate 22 oralternatively, the second coil 26 may be formed without a substrate 22using at least any of the fabrication techniques previously discussed.Alternatively, the first and second coils 24, 26 may be formed such thatthey are contactable to a surface 28 of a substrate 22. In this case,the first and second coils 24, 26 are removably contactable to thesurface 28 of a substrate 22. For example, the substrate 22 may providea temporary mechanical support for the antenna.

After the first and second coils 24, 26 have been formed, either with orwithout a substrate 22, at least one terminal is electrically connectedto at least one of the first and second coils 24, 26 (step 206). In anoptional fourth step 206, magnetic shielding materials may beincorporated within the structure of the antenna. In a fifth step 208,at least one terminal is electrically connected to at least one of thefirst and second coils 24, 26. In an optional sixth step 210, aselection circuit 118 may be electrically connected to at least one ofthe terminals or at least one of the first and second coils 24, 26. Inaddition, or in lieu of a selection circuit, an electrical switch 37 maybe electrically connected to at least one of the first and second coils24, 26 or at least one terminal.

FIGS. 8A-8C illustrate various embodiments of magnetic field intensityprofiles as a function of the number of turns that comprise the coil ofthe antenna of the present disclosure. As illustrated, in general,modifying the number of turns of the inductor affects the shape andprofile of the intensity of the magnetic field. This ability to modifythe position and/or strength of the magnetic field strength that isgenerated by the antenna can be desirable in optimizing data and energytransfer. In a preferred embodiment the strength and profile of themagnetic field can be custom tailored to meet the dimensions of variouselectronic devices. For example, by modifying the number of coils and/orposition of magnetic shielding materials that comprise the singlestructure antenna of the present disclosure, the intensity profile ofthe magnetic fields that is generated by the antenna can be modified. Itis noted that all the magnetic intensity profiles 8A-8C where taken ofsingle structure antennas having an outer coil width dimension of about150 mm and an outer coil length dimension of about 90 mm. In addition,the profile magnetic field measurements were taken from about 8 mm awayfrom the outer surface of the respective antennas. A relative intensityscale lies along the right side of each of the plots FIGS. 8A-8C. Asindicated by the intensity scale, the strongest magnetic field intensityhas a relative intensity of about 1 and is graphically representedhaving the darkest shade of black. The weakest magnetic field strengthhas a relative intensity of about 0.1 and is shown having the lightestshade of grey.

FIG. 8A illustrates an embodiment of a magnetic field intensity profiletaken of a single structure antenna comprising one outer coil having oneturn. The magnetic field intensity is greatest along the outer perimeterof the coil as illustrated by the darker shades of black which representthe strongest magnetic field intensity. While the strongest magneticfield intensities are along the outer perimeter, the weakest magneticfield intensity, represented by the lighter shade of grey, lies in thecentral area formed within the perimeter of the coil. Thus, thisembodiment is optimally configured for wireless energy transfer alongthe outer perimeter of the antenna.

FIG. 8B illustrates an embodiment of a magnetic field intensity profiletaken of a single structure antenna comprising a coil having two turns.As shown, the greatest magnetic field intensity lies more along an innerportion of the coil as compared to the field magnetic field intensityprofile of a coil having one turn as shown in FIG. 8A. The weakest fieldintensities of the two turn coil, shown by the lighter shade of grey,lie along the outer perimeter of the second turn of the coil which ispositioned towards the interior of the antenna. In comparison to thecoil having one turn as illustrated in FIG. 8A, the magnetic field alongthe central area of the antenna comprising a coil having two turns hasan overall increased magnetic field. Thus, as shown, adding anadditional interior turn moves the greatest field intensities closer tothe middle of the antenna.

FIG. 8C illustrates an embodiment of a magnetic field intensity profiletaken of a single structure antenna comprising a coil having threeturns, a first outer turn, a second inner turn and a third inner mostturn. Similar to the antenna comprising a coil with two turn, themagnetic field intensity of the three turn coil antenna shown in FIG. 8Cis the strongest, along the inner perimeter of the third innermost coiland central area of the antenna. Thus, the antenna comprising a coilhaving three turns has the strongest magnetic field in general in thecentral area of the antenna. In addition, the respective cornerlocations of the second inner turn of the coil also has increasedmagnetic field intensity. Therefore, such an antenna with a three turncoil is optimally designed to transfer electrical power and data in thecentral area of the antenna.

FIG. 9 illustrates a further embodiment of an antenna 140 of the presentdisclosure of a one piece construction having a unitary antenna body. Asillustrated, the antenna 140 is preferably formed from one piece of wireor filament 142 that is formed into the shape of the unitary bodyantenna 140 extending from a first wire end 149 to a second wire end153. In a preferred embodiment, the antenna 140 may be formed by astamping process in which the electrically conductive material is formedtogether in a mold and die stamp forming process using a metal blank. Ina preferred embodiment, the metal blank is positioned between the moldand die. The die is pressed against the metal blank within the mold thusforming the antenna body 140. In addition, the electrically conductivematerial that forms the unitary antenna body may be a metal bar, wire,or filament that is stamped out of a sheet of metal. Alternatively,antenna 140 may be formed by a wound wire process whereby the unitarybody of the antenna 140 is formed from a single wire that is curved orwound into the desired shape of the antenna 140 comprising a pluralityof turns.

The antenna 140 is preferably formed of a continuous wire form havingmultiple electrical connection points 148, 150, 152 that are disposedalong various portions of the wire 142 of the antenna 140. The pluralityof electrical connection points 148, 150, 152 or electrical “taps”create multiple inductor coils having different inductances thatcomprise the antenna 140 of the present disclosure.

As illustrated in FIG. 9, a first electrical connection point 148 thatis disposed at the first end 149 of the wire 142 of the antenna 140serves as the common electrical connection. A second electricalconnection point 150 is positioned along the third turn of the antenna140 serves as the “low” inductance electrical connection. A thirdelectrical connection point 152 is disposed at the second end 153 of theantenna 140 serves as the “high” inductance electrical connection of theantenna 140. In an embodiment, terminal leads 154, 156, 158, such aselectrically conductive wires, may be attached to these electricalconnection points to create antenna terminals. Thus, as shown, the firstelectrical connection point 148 may serve as the first terminal 34, thethird electrical connection point 152 may serve as the second terminal36 and the second electrical connection point 150 may serve as the thirdterminal 35. Furthermore, the various first, second and third electricalconnection points 148, 150, 152 form the multiple inductor coils of theantenna 140. As illustrated, a first outer inductor coil portion 144having N₁ number of turns is disposed between the first and secondelectrical connection points 148, 150 and a second inductor coil portion146 having N₂ number of turns is disposed between the second and thirdelectrical connection points 150, 152. Similar to the previous singlestructure antenna embodiments, the unitary body antenna 140 maycomprises more than three terminal connections which can be electricallyconnected to generate a multitude of operating frequencies and/orinductances. In addition, a turn gap 161 may be positioned betweenadjacent turns of the first and second inductor coils portions 144, 146.Specifically, the turn gap 161 is a space disposed between adjacentwires 142 of the antenna 140. In a preferred embodiment, the turn gap161 may extend from about 0.1 mm to about 50 mm.

Preferably, the unitary body antenna 140 illustrated in FIG. 9 isself-standing and does not require the support of a substrate. However,it is contemplated that such an antenna structure may be contactable toa substrate surface. Substrates may include, but are not limited to, adielectric material and/or a magnetic field blocking material such as aferrite material as previously discussed. In addition, such an antennaconstruct may be incorporated within an article of clothing, furniture,an electrical appliance or a vehicle.

FIG. 10 is a flow chart that illustrates an embodiment of method offabricating the single structure multi-mode antenna 140 having a unitaryantenna body. As shown in the flow chart, in a first step 212, a metalblank is provided. In a second step 214, a die and mold that are used toform the metal blank into the form of the antenna 140 are provided. In athird step 216, the die is used to form the blank metal into the form ofthe unitary body antenna 140. In a fourth step 218, at least oneterminal is electrically connected to at least one of the first andsecond coil portions 144, 146. In an optional fifth step 220, aselection circuit 118 may be electrically connected to at least one ofthe terminals or at least one of the first and second coil portions 144,146. In addition, or in lieu of a selection circuit 118, an electricalswitch 37 may be electrically connected to at least one of the first andsecond coil portions 144, 146 or at least one terminal.

It is further contemplated that the various embodiments of the singlestructure antenna of the present disclosure may comprise a plurality ofterminals greater than three. FIG. 11 illustrates a theoretical examplein which a single structure antenna of the present disclosure maycomprise a plurality of n+1 number of terminal connections. As shown,the antenna of the present disclosure may comprise three, four, five ormore terminal connections which can be electrically connected togenerate an infinite number of operating frequency bands and/orinductances.

FIG. 11 illustrates a theoretical example of a single structure antennaof the present disclosure that comprises an indefinite number ofinductors, Ln in which each of the multitude of inductors may have adifferent inductance. Furthermore, as illustrated, the respectiveinductors, L₁ through L_(n) preferably comprise a terminal connection T₁through T_((n+1)) or electrical “tap” that is electrically connected toat least a portion of the respective inductor coil. Therefore, it ispossible to create a single structure antenna that may be selectivelytuned to exhibit an unlimited number of frequencies and/or inductancessuch that the antenna of the present disclosure can be tuned to an exactfrequency or frequencies.

FIGS. 12A-12C illustrate embodiments of electrical switch configurations160 that may be used to electrically connect and/or disconnect thevarious terminals that may comprise the single structure antenna of thepresent disclosure. It is noted that FIGS. 12A-12C correlate torespective embodiments illustrated in FIGS. 8A-8C. As illustrated inFIGS. 12A-12C, the exemplar antenna comprises three inductors L₁-L₃having four terminal connections T₁-T₄. A multiple of electricalconnection points 162A-162P are positioned at various locations alongthe antenna. In addition, the antenna comprises a multitude ofelectrical switches 164, 166, 168, 170, 172, 174, 176 and 178 that arepositioned along the antenna and are designed to electrically connectand/or disconnect the various electrical connection points along theantenna. For example, electrical switch 164 is shown electricallyconnecting electrical connection points 162A and 162B, electrical switch172 is shown electrically connecting electrical connection points 162Mand 162N. Thus, by electrically connecting a certain combination ofelectrical connection points 162A-162P along the single structureantenna by at least one of the various electrical switches 164-178 theantenna can be tuned to a desired operating frequency, frequenciesand/or inductances that are suitable to wirelessly transfer or receiveelectrical energy and/or data signals as desired.

Furthermore, any of these multitude of switches may be turnedelectrically “on” or “off” as desired as the antenna operates. It isnoted that electrically active, i.e., electrically connected, electricalconnection points are illustrated as black filled circles whereasnon-active electrical connection points, i.e., electrical connectionpoints that are electrically disconnected, are shown as unfilledcircles. It is further noted that a microprocessor (not shown) orcircuit board (not shown) may be used to control the combination ofswitches that are turned “on” or “off”. In addition, the electricalswitch may comprise a multitude of different electrical switches.Examples of which may include, but are not limited to, an electricaltoggle switch, a rocker switch, a push button switch, an inline switch,switched capacitor networks, and filter networks that utilize inductorsand/or capacitors. As defined herein, an electrical switch is anelectrical component that can either connect or disconnect an electricalcurrent, voltage, signal or combinations thereof, along an electricalpathway. A switch can also divert an electrical current, voltage, signalor combinations thereof, from one electrical conductor to another. Anelectrical switch that is in an “on” position is defined as allowing anelectrical signal or electrical current or voltage to pass therethroughand thus is electrically connected. An electrical switch that is in an“off” position is defined as prohibiting an electrical signal orelectrical current or voltage to pass therethrough and thus iselectrically disconnected.

FIG. 12A illustrates an embodiment in which the antenna of the presentdisclosure is configured with the first and fourth terminals T1, T4electrically connected such that the antenna exhibits an inductanceequal to the combination of the first, second and third inductors L₁, L₂and L₃. Specifically, as illustrated, electrical switches 164, 166, 172and 178 are closed and electrical connection points 162A, 162B, 162C,162D, 162M, 162N, 1620 and 162P are electrically closed thereby allowingelectrical current to pass therethrough.

FIG. 12B shows an embodiment in which the antenna is configured with thefirst and second terminals T1, T2 electrically connected so that theantenna exhibits an inductance comprising the first inductor L₁.Specifically, as illustrated, electrical switches 164, 166, and 170 areelectrically closed and electrical connection points 162A, 162B, 162C,162E, 162F, and 162H are electrically active. All other electricalswitches and electrical connection points are illustrated to beelectrically open.

FIG. 12C shows an embodiment of the antenna in which the first and thirdinductors L₁, L₃ that comprise the antenna are electrically connected.As illustrated, an electrical switch connections bypass the secondinductor L₂ within the antenna. A first bypass switch electricallyconnects the first inductor to a bypass portion of the antenna and asecond bypass switch electrically connects the first inductor L₁ to thethird inductor L₃. Specifically, as illustrated, electrical switches164, 168, 174 and 178 are electrically closed and electrical connectionpoints 162A, 162B, 162C, 162E, 162F, 162G, 1621, 162K, 162L, 162N, 1620and 162P are electrically active. FIG. 13 is a flow chart thatillustrates an embodiment of operating the multi-mode single structureantenna of the present disclosure. As shown, in a first step 222, amulti-mode single structure antenna of the present disclosure isprovided. In a second step 224, a connection between at least twoterminals is selected. Thus, by connecting two of the at least threeterminals enables an operator to select a desired receiving ortransmitting antenna frequency. In addition, by connecting two of the atleast three terminals enables an operator to select a desired inductancethat is exhibited by the antenna. To tune the antenna to a differentfrequency or inductance, a second connection between two of the at leastthree terminals having a different electrical connection configurationof that of the first is made. The electrical connections betweenterminals may be made manually or alternatively, can be madeautomatically by a machine such as a computer or device comprising aprocessing unit. As previously mentioned, the electrical connectionsbetween terminals can be made via an electrical switch 37 and/or aselection circuit 118. Thus, it is contemplated that the singlestructure antenna of the present disclosure is capable of being tuned toa plurality of unlimited frequencies or inductances by connectingdifferent terminals or electrical points positioned along at least thefirst and second coils 24, 26. It is appreciated that variousmodifications to the inventive concepts described herein may be apparentto those of ordinary skill in the art without departing from the spiritand scope of the present disclosure as defined by the appended claims.

As used herein, the phrase “at least one of” preceding a series ofitems, with the term “and” or “or” to separate any of the items,modifies the list as a whole, rather than each member of the list (i.e.,each item). The phrase “at least one of” does not require selection ofat least one of each item listed; rather, the phrase allows a meaningthat includes at least one of any one of the items, and/or at least oneof any combination of the items, and/or at least one of each of theitems. By way of example, the phrases “at least one of A, B, and C” or“at least one of A, B, or C” each refer to only A, only B, or only C;any combination of A, B, and C; and/or at least one of each of A, B, andC.

The predicate words “configured to”, “operable to”, and “programmed to”do not imply any particular tangible or intangible modification of asubject, but, rather, are intended to be used interchangeably. In one ormore embodiments, a processor configured to monitor and control anoperation or a component may also mean the processor being programmed tomonitor and control the operation or the processor being operable tomonitor and control the operation. Likewise, a processor configured toexecute code can be construed as a processor programmed to execute codeor operable to execute code.

A phrase such as “an aspect” does not imply that such aspect isessential to the subject technology or that such aspect applies to allconfigurations of the subject technology. A disclosure relating to anaspect may apply to all configurations, or one or more configurations.An aspect may provide one or more examples of the disclosure. A phrasesuch as an “aspect” may refer to one or more aspects and vice versa. Aphrase such as an “embodiment” does not imply that such embodiment isessential to the subject technology or that such embodiment applies toall configurations of the subject technology. A disclosure relating toan embodiment may apply to all embodiments, or one or more embodiments.An embodiment may provide one or more examples of the disclosure. Aphrase such an “embodiment” may refer to one or more embodiments andvice versa. A phrase such as a “configuration” does not imply that suchconfiguration is essential to the subject technology or that suchconfiguration applies to all configurations of the subject technology. Adisclosure relating to a configuration may apply to all configurations,or one or more configurations. A configuration may provide one or moreexamples of the disclosure. A phrase such as a “configuration” may referto one or more configurations and vice versa.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” or as an “example” is not necessarily to be construed aspreferred or advantageous over other embodiments. Furthermore, to theextent that the term “include,” “have,” or the like is used in thedescription or the claims, such term is intended to be inclusive in amanner similar to the term “comprise” as “comprise” is interpreted whenemployed as a transitional word in a claim. Furthermore, to the extentthat the term “include,” “have,” or the like is used in the descriptionor the claims, such term is intended to be inclusive in a manner similarto the term “comprise” as “comprise” is interpreted when employed as atransitional word in a claim.

All structural and functional equivalents to the elements of the variousaspects described throughout this disclosure that are known or latercome to be known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe claims. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the claims. No claim element is to be construedunder the provisions of 35 U.S.C. §112, sixth paragraph, unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

Reference to an element in the singular is not intended to mean “one andonly one” unless specifically so stated, but rather “one or more.”Unless specifically stated otherwise, the term “some” refers to one ormore. Pronouns in the masculine (e.g., his) include the feminine andneuter gender (e.g., her and its) and vice versa. Headings andsubheadings, if any, are used for convenience only and do not limit thesubject disclosure.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of what may be claimed, but ratheras descriptions of particular implementations of the subject matter.Certain features that are described in this specification in the contextof separate embodiments can also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

What is claimed is:
 1. An antenna, comprising: a) a first conductivewire forming a first coil having N₁ number of turns with spaced apartfirst and second first coil ends, the first coil contactable to asubstrate surface, wherein the first coil is capable of generating afirst inductance; b) a second conductive wire forming a second coilhaving N₂ number of turns with spaced apart first and second second coilends, the second coil capable of generating a second inductancepositioned within an inner perimeter formed by the first coil; c) afirst terminal electrically connected to the first end of the firstcoil, a second terminal electrically connected to the second end of thesecond coil and a third terminal electrically connected along either ofthe first or second coils; and d) wherein a tunable inductance isgeneratable by selecting a connection between two of the first, secondand third terminals.
 2. The antenna of claim 1, further comprising a gapdisposed between the inner perimeter of the first coil and an outerperimeter of the second coil.
 3. The antenna of claim 2, wherein the gapis at least about 0.1 mm.
 4. The antenna of claim 1, wherein the firstconductive wire comprises two or more filars electrically connected inparallel.
 5. The antenna of claim 1, wherein the second conductive wirecomprises two or more filars electrically connected in parallel.
 6. Theantenna of claim 1, wherein the first terminal is electrically connectedto the first end of the first coil, the first end of the first coildisposed at an end of the first wire of the first coil located at anoutermost first coil perimeter, the third terminal is electricallyconnected to the first end of the second coil positioned at a secondcoil outer perimeter, and the second terminal is electrically connectedto the second end of the second coil located along an interior perimeterof the second coil pattern.
 7. The antenna of claim 1, wherein aselection circuit is electrically connected to at least one of thefirst, second, and third terminals.
 8. The antenna of claim 7, whereinthe selection circuit comprises at least one component selected from thegroup consisting of a capacitor, a resistor, and an inductor.
 9. Theantenna of claim 1, wherein N₁ is at least one and N₂ is at least two.10. The antenna of claim 1, wherein N₂ is greater than N.
 11. Theantenna of claim 1, wherein each terminal has a terminal lead portionthat extends between a coil connection point and a terminal end, thecoil connection point electrically connected to either of the first andsecond conductive wires of the first and second coils respectively, andwherein the terminal lead portion extends over at least a portion ofeither of the first and second conductive wires of the first and secondcoils respectively.
 12. The antenna of claim 11, wherein a plurality offirst vias are positioned adjacently along a right side of a length ofthe terminal lead portion and a plurality of second vias are positionedalong a left side of the length of the terminal lead portion and opposedfrom the plurality of first vias so that each of the plurality of firstvias opposes one of the plurality of second vias, wherein the respectiveopposing vias of the plurality of first and second vias are electricallyconnected to the same conductive wire of either of the first or secondcoils, thereby establishing a conductive electrical path therebetweenthat bypasses the terminal lead portion.
 13. The antenna of claim 1,wherein at least the first conductive wire or the second conductive wirehas a variable wire width.
 14. The antenna of claim 1, the antennahaving a quality factor greater than
 10. 15. The antenna of claim 1,wherein an electrical signal selected from the group consisting of adata signal, an electrical voltage, an electrical current, andcombinations thereof is receivable by at least the first and secondcoils.
 16. The antenna of claim 1, wherein an electrical signal selectedfrom the group consisting of a data signal, an electrical voltage, anelectrical current, and combinations thereof is transmittable by atleast the first and second coils.
 17. The antenna of claim 1, whereinthe substrate comprises material composed of an electrically insulativematerial selected from the group consisting of a polyimide, an acrylic,fiberglass, polyester, polyether imide, polytetrafluoroethylene,polyethylene, polyetheretherketone (PEEK), polyethylene napthalate,fluropolymers, copolymers, a ceramic material, a ferrite material, andcombinations thereof.
 18. The antenna of claim 1, wherein the antenna iscapable of receiving or transmitting within a frequency band selectedfrom the group consisting of about 100 kHz to about 250 kHz, about 250kHz to about 500 kHz, 6.78 MHz, 13.56 MHz, and combinations thereof. 19.The antenna of claim 1, wherein the antenna is capable of receiving ortransmitting at frequencies of at least 100 kHz.
 20. The antenna ofclaim 1, wherein a tunable operating frequency is generatable byselecting a connection between two of the first, second, and thirdterminals.